gb/src/work_ram.rs

76 lines
1.7 KiB
Rust

use crate::bus::BusIo;
const WORK_RAM_SIZE: usize = 0x1000;
const VARIABLE_WORK_RAM_SIZE: usize = WORK_RAM_SIZE;
const WORK_RAM_START_ADDRESS: usize = 0xC000;
const VARIABLE_WORK_RAM_START_ADDRESS: usize = 0xD000;
#[derive(Debug)]
pub(crate) struct WorkRam {
bank: Box<[u8; WORK_RAM_SIZE]>,
}
impl BusIo for WorkRam {
fn write_byte(&mut self, addr: u16, byte: u8) {
self.bank[addr as usize - WORK_RAM_START_ADDRESS] = byte;
}
fn read_byte(&self, addr: u16) -> u8 {
self.bank[addr as usize - WORK_RAM_START_ADDRESS]
}
}
impl Default for WorkRam {
fn default() -> Self {
Self {
bank: Box::new([0u8; WORK_RAM_SIZE]),
}
}
}
#[derive(Debug, Clone, Copy)]
enum BankNumber {
One = 1,
Two = 2,
Three = 3,
Four = 4,
Five = 5,
Six = 6,
Seven = 7,
}
#[derive(Debug)]
pub(crate) struct VariableWorkRam {
current: BankNumber,
bank_n: Box<[[u8; VARIABLE_WORK_RAM_SIZE]; 7]>, // 4K for Variable amount of Banks (Banks 1 -> 7) in Game Boy Colour
}
impl Default for VariableWorkRam {
fn default() -> Self {
Self {
current: BankNumber::One,
bank_n: Box::new([[0u8; VARIABLE_WORK_RAM_SIZE]; 7]),
}
}
}
impl VariableWorkRam {
fn set_current_bank(&mut self, bank: BankNumber) {
self.current = bank;
}
fn get_current_bank(&self) -> &BankNumber {
&self.current
}
}
impl BusIo for VariableWorkRam {
fn write_byte(&mut self, addr: u16, byte: u8) {
self.bank_n[self.current as usize][addr as usize - VARIABLE_WORK_RAM_START_ADDRESS] = byte;
}
fn read_byte(&self, addr: u16) -> u8 {
self.bank_n[self.current as usize][addr as usize - VARIABLE_WORK_RAM_START_ADDRESS]
}
}